A miniature VT102 running a miniature PDP11


We spend a lot of time studying retro computing in the form of games and personal computers, but it’s true that minicomputers are less common than hardware projects. It might be the size, cost, or even the relative rarity of the original machines, but DEC minicomputers are a bit unusual here. [Sprite_TM] didn’t buy us a PDP11 or VT102 terminal, but he did the next best thing in the form of a miniature working VT102 which also hides a PDE11 emulator. It runs Tetris, which was originally developed on a Russian clone of the PDP11 architecture, and the 2.1BSD operating system.

Everything is powered by an ESP32 module and the PDP11 emulator is the well-known SIMH software. Porting this into the slightly limited microcontroller environment required some compromises, namely the network stack and the configuration interface. In a particularly clever move [Sprite_TM] Enabled BSD networking by writing an ESP32 layer that takes network packets via SIMD directly from BSD. It includes its own DHCP client and wireless network configuration tool, allowing an old UNIX-derived operating system from the 1970s to connect to the 21st century Internet through an emulator whose network code was deleted.

The case is an OpenSCAD masterpiece, a complete miniature VT102 unit with a small LCD display which, when printed on a resin printer, is a remarkable facsimile of the real thing. It doesn’t have a keyboard equivalent, but even with a miniature Bluetooth board it still looks quite impressive. In the video below, he boots into 2.1BSD and, more importantly, since it’s a server OS, connects to it from his laptop and plays a game of Zork.

[Sprite_TM] brought us so many awesome projects over the years using the ESP32 and other parts. Maybe you have a favorite, but for us it’s the tiny PocketSprite Game Boy-like handheld console.


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